Pilot experiment showing the selective joining of a V gene to the Ig-cassette by TS-jPCR. (A) An agarose gel stained with ethidium bromide showing the TS-jPCR results. Lane 1: Ig-cassette, lane 2: tailed mock DNA fragment, lane 3: tailed V gene fragment, lane 4: mixture of the mock and V gene fragments, lane 5: amplified product with the Ig-cassette and water, lane 6: amplified fragment with the Ig-cassette and mock DNA fragment, lane 7: amplified fragment with the Ig-cassette and V gene fragment, lane 8: amplified fragment with the Ig-cassette and a mixture of mock DNA and V gene fragments. Lanes 5-8: each lane contains 1 μl from a 25-μl PCR. The arrow indicates the size of the Ig-expression construct. M, 1 kb DNA ladder. (B) DNA sequence chromatogram of the fragment in lane 8. The arrow indicates the boundary between the V gene and the Ig-cassette. The blue horizontal bar indicates the heavy chain constant sequence, and the red bar indicates the variable sequence.